ABSTRACT
China and G7 countries contribute 70% global GDP and 55% global carbon emissions. The carbon leakage between China and G7 is a crucial issue in achieving the synergetic emission abatement globally. The motivation of this study is to evaluate the embodied carbon transfer between China and G7 in the trade between 2000 and 2014, and investigate the driving factors that impact the embodied carbon trend. A multiregional input–output (MRIO) model based on the WIOD database is constructed, and a structural decomposition analysis (SDA) is employed. The results indicate that China plays the role of net exporter of embodied carbon in trade with G7, which mainly flows to the US (5825.67 Mt), Japan (3170.36 Mt) and Germany (1409.93 Mt). However, China’s embodied carbon exports to the G7 show an inverted U-shaped trend with a turning point after financial crisis, while the G7’s embodied carbon exports to China continue to rise. The conclusion is that to achieve the climate goal of carbon neutrality, it is not enough to rely solely on the low-carbon transition on the production side, the demand side should also be adjusted.
ABSTRACT
In New Zealand, housing is typically low density, with light timber framing being the dominant form of construction with more than 90% of the market. From 2020, as a result of the global pandemic, there was a shortage of timber in New Zealand, resulting in increased popularity for light steel framing, the main alternative to timber for housing. At the same time, the New Zealand government is committed to sustainability practises through legislation and frameworks, such as the reduction of whole-of-life carbon emissions for the building industry. New Zealand recently announced reducing its net greenhouse gas emissions by 50% within 2030. Life cycle assessment (LCA) is a technique for assessing the environmental aspects associated with a product over its life cycle. Despite the popularity of LCA in the construction industry of New Zealand, prior research results seem varied. There is no unified NZ context database to perform an LCA for buildings. Therefore, in this paper, a comprehensive study using LCA was conducted to quantify and compare the quantity of carbon emissions from two commonly designed houses in the Auckland region, one built from light timber and the other from light steel, both designed for a lifespan of 90 years. The cradle-to-cradle system boundary was used for the LCA. From the results of this study, it was found that the light steel house had 12.3% more carbon in total (including embodied and operational carbons) when compared to the light timber house, of which the manufacturing of two houses had a difference of 50.4% in terms of carbon emissions. However, when the end-of-life (EOL) analysis was included, it was found that the extra carbon could be offset due to the steel’s recyclability, reducing the amount of embodied carbon in the manufacturing process. Therefore, there was no significant difference in carbon emissions between the light steel and the light timber building, with the difference being only 12.3%.